Archives For projects for kids

The Martian: Many of us watched and loved the movie. Some of us read the book. A few of us got inspired to use the story to teach plant science to students.

PHOTO: Book cover art for The Martian: a novel

If you are a science enthusiast, I highly recommend reading the book.

The Martian by Andy Weir tells the fictional story of NASA astronaut and botanist Mark Watney, who becomes stranded alone on Mars and has to figure out how stay alive until the next NASA mission returns to rescue him. He plants six potatoes and successfully propagates a crop of potatoes in Martian dirt fertilized with human poop.

The story got me wondering if we could replicate Martian soil with local ingredients and use it for plant experiments. So I contacted the Garden’s soil scientist, Louise Egerton-Warburton, and asked her if this was possible. She responded with a recipe:

  • Mix two parts crushed volcano rock, two parts basalt dust, one part sand, plus 0.2 parts feldspar
  • Autoclave (heat to very high temperature) three times to kill microbes
  • Experiment away!

You know you work in a great place when you can ask a colleague for directions for making Martian soil and you get an immediate, enthusiastic response with suggestions for how to use it. I acquired the materials and cooked up a batch.

PHOTO: a box of basalt, a cup of sand, a bag of feldspar, and a glass beaker containing the Martian soil mixture

I keep the ingredients for Martian soil in my office, in case Mark Watney drops by. Because you just never know. Matt Damon and Andy Weir are also welcome, but I hear they have both moved on to other projects.

One important thing I must mention: technically speaking, this mixture is not truly “soil.” Soil is the upper layer of material on the Earth that serves as an ideal medium for growing plants. It contains inorganic minerals from weathered and broken rocks combined with organic material from the decomposed remains of dead plants and animals. Real soil hosts microscopic bacteria and fungus that facilitate a cycling of nutrients through the ecosystem and convert minerals to a form plants can absorb and use. Soil also supports many little macroscopic critters, like worms and mites, that increase the porosity and affect other properties of the mixture.

The substance we would find on the surface of Mars is called regolith, which is mineral particles that result from weathering of rocks. Since my mixture is an approximation of what might be found on Mars, but made from Earth-sourced ingredients, it should actually be called simulated Martian regolith. But that’s a mouthful, so from here on I’m going to call it Martian soil and ask you, dear readers, to accept the inaccuracy for the sake of simplicity. OK?

I took my Martian soil and set out to answer my first question: what happens if we try to plant seeds in this stuff? Put another way, is it possible to grow plants in Martian soil without adding anything? To answer this question, I took a polystyrene egg carton and planted marjoram seeds (because I had some laying around) in my Martian soil and in some Earth potting soil for comparison.

PHOTO: an 18 egg egg carton that has the 9 cells on the left planted with Martian soil and the nine cells on the right planted in earth potting soil; marjoram has sprouted in all 18 cells.

It was overcast outside when I took this picture in the greenhouse—you’ll have to look closely to see that the marjoram seeds sprouted in both Martian and Earth soils. So far, so good.

The Martian soil is completely different from the potting soil in appearance and texture, and it responds differently when watered. Shortly after the seeds germinated in all of the cells, the Mars side went south. It didn’t hold water very well; it dried out and became hard, almost like concrete. It was no surprise that all of the seedlings on the Mars side died soon after germination. Plants on the Earth side continued to grow and thrive.

PHOTO: The same 18 cell egg carton now has nine Martian soil cells with no plants and nine cells with healthy marjoram growing in Earth potting soil.

It is clear from this test that the Martian soil needs to be amended to grow plants. We were told this in The Martian, but now I know it from personal experience. We can use our observations to understand why Martian soil is not a good medium for plants. That’s real science learning!

In the book, Watney used a bucket of Earth soil and human waste to amend the Martian soil for his potato crop. The book and the movie differ on this part—likely because the process required to make Martian soil suitable for growing potatoes was long and tedious. It wouldn’t make for riveting cinema. Instead of cultivating the soil over time, movie-Watney planted a spoonful of rehydrated human poop next to each piece of potato. 

While movie-Watney’s actions remind us of stories about the Pilgrims teaching the indigenous people to place a piece of fish next to each kernel of corn to improve the crop yield, there are some problems with applying this method to our Martian soil. The Martian soil would still lack sufficient organic materials and therefore not be able to hold water (as I demonstrated with my marjoram seed experiment). There would be an insufficient population of microbes to break down the human waste. Furthermore, the fecal matter might be so concentrated in nutrients that it could actually be toxic to the potato plants. I don’t believe it would actually work.

This compelled me to do some myth busting for my next experiment: since “humanure” would be unsafe—and gross!—I used worm poop, or vemicompost, which I have in plentiful supply from worm bins in our Learning Center nature laboratory. Also, I discovered that you can order “Martian Regolith Simulant” from a company online (who knew?). Although it’s expensive, it saved me the effort of crushing rocks, so I’m using it from now on.

This time I planted russet potato pieces and some sweet potatoes that had sprouted in my pantry at home (oops!) in azalea pots. I set up three conditions: Martian soil, Martian soil plus vermicompost, and Earth potting soil for comparison. 

 

PHOTO: Three 10-inch pots with potatoes planted in each of the soil conditions: Martian soil, potting soil, and mixture of Martian soil with vermicompost

In spite of my doubts, I’m actually hoping that the potatoes in Martian soil plus vermicompost out-perform the potatoes in plain Martian soil, because bringing worms on a space voyage could prove to be a good solution for future colonists on Mars! But we’ll have to wait and see.

Underlying these experiments (and few other I have tried) is a basic investigation of what plants need to survive. By testing to find the right combination of Martian soil and amendments, and limiting solutions to those that could be transported by a spaceship to another planet, we are using engineering practices because we are trying to solve a problem. This is real-world science and engineering that students could do in the classroom. 

PHOTO: Kathy J. sitting in her office wearing a space suit.

Here I am, working on my next astro-botany experiment, for myself, for teachers, and for science!

Besides satisfying my personal curiosity, these experiments are paving the way for some science lessons we are writing for teachers and students.

If you are a teacher interested in learning more about how to teach NGSS-aligned life science lessons using Martian soil, sign up for our workshop, STEM: Growing Plants in Martian Soil on Saturday, December 2, 2017. And watch for other Martian soil training opportunities in the future. 

We may never need to grow crops in Martian soil. But as we investigate the challenges of colonizing another planet, we can learn more about what plants need to thrive and also develop a genuine appreciation for how amazing our Earth soil is.


©2017 Chicago Botanic Garden and my.chicagobotanic.org

DIY Living Plant Wall

Kathy J. —  May 15, 2017 — 1 Comment

This year, the Living Wall in the Grunsfeld Children’s Growing Garden needed to be replanted. The metal cells that hold the plants to the wall were removed and taken to the Garden’s greenhouse nursery to grow new plants before placement outside for the summer.

This left us with four empty walls at the entrance to the Growing Garden. So we decided to get creative. We made an “alternative” living wall. 

PHOTO: sixteen cone-shaped pockets containing small plants are displayed on the brown walls.

The south-facing wall is now covered with burlap pocket planters containing alyssum, lettuce seedings, grass, and coriander.

Our carpenters covered foam boards with brown burlap and installed these panels on the living wall frame where the plant cells had been removed. Students from the Garden’s Nature Preschool planted seeds and transplanted seedlings into small pots. We placed the plants into colored burlap planters and pinned them to the foam walls, and voila! We have a vertical garden again.

You can do this at home. Making planting pockets is simple and fun.

  1. Plant seeds or transplant small plants and let them sprout. We used biodegradable Fertilpots, but you could also start seeds in egg cartons, newspaper pots, or plastic pots.

2. Cut the burlap into squares that are twice as long and wide as the pots.

PHOTO: The picture shows the size of the burlap square next to the pot that was used.

Our Fertilpots were 4″ tall, so I cut the fabric roughly into 8″-x-8″ squares. This does not need to be exact.

3. Fold the square in half diagonally and sew a seam along the side. You can use a heavy duty needle with a sewing machine or do this by hand with a darning needle. It might be possible to use a hot glue gun to make the seam, but I did not try this.

PHOTO: This shows what the burlap looks like after it is sewed in half.

I used a sewing machine because I made more than 100 of these. They could be sewn by hand.

4. Turn the triangle inside out to form the pocket. Slip the planted pot into the pocket and get ready to hang it on a wall.

PHOTO: This shows the pocket with a pot inside.

The seam side of the pocket is the back, and the pointed front top can either be folded down or cut off.

5. To hang on the wall, pinch the extra fabric so the burlap fits snugly around the pot. Fold down the point in front or cut it off—your choice. Push a long pin through the pot and the fabric and pin the pocket to the wall. (I had pins used by our horticulturists to propagate cuttings; you could use T-pins or other pins with large heads.) You could also lace a ribbon around the top of the pocket and cinch the fabric, then hang the planter by the ribbon.

PHOTO: The picture shows a hand holding the fabric to make the pocket fit around the pot.

Gathering the extra fabric will help hold the pot better, and it will look neater on the wall.

Students in our Nature Preschool enjoyed helping to grow the plants and pin them to the Living Wall. Each child wanted to place his or her planter next to a friend’s planter so they could grow close together.

wall KJ with girl

Just for fun, we experimented with some other kinds of planters, including plastic bottles and shoes.

PHOTO: a 2 liter plastic bottle turned sideways and filled with soil and oregano plants is pinned to the wall.

If you want to try growing a plant in a 2-liter bottle, cut a rectangular opening in the side of the bottle, poke six to eight holes on the opposite side for drainage, fill with soil, plant, and hang it up.

The preschoolers are fascinated by the soda bottle planter. They like to look in the round opening on the side. The toddler shoe makes everyone smile. We may add more surprising planters over the next few weeks, just to keep it interesting.

PHOTO: a toddler shoe with alyssum growing in it is laced with twine and hanging on the wall,

An old shoe can become a whimsical planter that sparks imagination.

If you decide to try something like this at home, be advised that the small pots need to be watered frequently (ours need watering daily) because they tend to dry out faster than larger containers. It’s a good project for young children because they will get to do a lot of watering without harming the plants.

Our “alternative living wall” is only temporary. Stop by the Grunsfeld Children’s Growing Garden between now and June 12 to see how it’s growing. After that, the real living wall will be installed for the rest of the year.


©2017 Chicago Botanic Garden and my.chicagobotanic.org

A few years ago, my Daisy and Brownie Girl Scout troop was working on their Household Elf badge. We needed a fun way to teach about conserving water at home—not a lecture—because let’s face it, after a full day of school, 6- to 9-year-old girls would will not sit still and listen to another lesson. I decided to make a board game for them. The main message of this game was a really important one: in Chicago, all of our water for drinking, cleaning, and recreation comes from Lake Michigan. If we waste water, then we waste the lake. It is that simple. 

PHOTO: Board, cups, beads, and game tokens are arranged for the water conservation game.

The Water Conservation Game is set up and ready to play.

The girls responded very well to the activity. I am sharing it on the Garden’s blog for others to use, because at the Chicago Botanic Garden, we would also like people to understand the importance of conserving water from our lakes and other sources. Obviously this game was created for Chicago residents, but the same principles apply everywhere, in every community. The game could be adapted for another location by replacing the image of the Lake Michigan with an image to represent the local water source. (For most cities, that is groundwater.)

Download the game board

I discovered, to my surprise, that many of my Brownie Scouts were not familiar with board games. Most millennials have lots of experience pushing virtual buttons on a screen and competing against friends in cyberspace, but tossing a die and moving a token around a board with actual friends? Not so much. Anyone replicating this activity may find they need to explain how a game like this works. Also, it was also important to require that the players actually read the board squares in order to understand why they are taking two or three or ten beads as they move around the board. Having a discussion at the end of the game proved essential to getting the message across. 

After playing the game with my Scouts, I shared it with a group of middle school girls who were studying conservation in an after-school program. Believe it or not, it worked well with the older students, too. In fact, they loved it—mostly because they got to make a bracelet. But hey, whatever works, right?! 

To use this activity with your group, make one complete game set for every three to five students.

A game set includes:

  • 1 game board, printed on 11″ x 17″ paper
  • 1 six-sided die
  • Place marker tokens; one per person (these can be any small object, or borrow them from another board game set)
  • About 100 pony beads (I like to use transparent blue plastic beads because they look like water)
  • 1 small cup per person, plus one cup to serve as the bead reservoir
  • Elastic thread cut into 8-inch pieces; one per person (this is to make bracelets)

Game rules

  1. The object of this game is to move around the board and be the person who uses the least water. Remind players that every time we use water, we take a little more out out of Lake Michigan.
  2. Put about 100 beads in a cup and place it in the middle of the lake. The beads represent water from Lake Michigan. Players will keep track of how much water they use by collecting the beads in their cups as they move around the board.
  3. Players place their markers on “Start.” Each player rolls the die; the player with the highest roll goes first. If there is a tie, roll again to break the tie. The player sitting on the left of the first person goes second and players take turns going around the board in a clockwise direction. (I had to explain this to the girls in my troop.)
  4. The first player rolls the die and moves that number of spaces on the board in the direction of the arrows. The player lands on a square, reads what it says and follows the directions, collecting the beads from the reservoir and putting them into her own cup. Each player takes a turn and until everyone has moved around the board once and ended at the lake. It is not necessary to roll a perfect number to reach the end.
  5. When everyone is swimming in the lake at the end, tally up the number of beads each player has collected. The player with the fewest beads wins, because she used less water than the other players. 
  6. Return beads to the reservoir and play again once or twice to give others a chance to win. 

What is this game telling us? 

Ask the players to think about water use. The questions below can stimulate discussion. This can be brief, but it is important to reinforce the message that all of our water comes from Lake Michigan and we need to be responsible with water use.

  • What activities in the game used a lot of water and made someone lose the game?
  • What are some ways people waste water?
  • What practices use less water? 
  • What would happen if everyone was careless and used all the water from the lake? 
  • What can you do at home to reduce the amount of water you take out of Lake Michigan? 

 

PHOTO: Package of 620 pony beads and a bracelet made from the beads

Transparent blue pony beads resemble water and make a nice bracelet.

Make a water bead bracelet

For a fun wrap up, each player can make a bracelet using the beads and elastic string. Wear the bracelet to remember to try and use less water at home. The bracelet makes a nice reward for learning outside the classroom.

One last important note

When teaching young children about water conservation, avoid the temptation to bring up stories of environmental problems that are beyond their ability to solve right now in their lives, like unpleasant images of industrial pollution, drought, and famine. Child development experts will tell you that when we burden children with messages about how they need to help save the planet, we actually do more harm than good by making them feel overwhelmed, hopeless, and less inclined to adapt sustainable habits. Focus on things they can do, like turning off the water when they brush their teeth. It is enough that they learn not to use more water than they need at home so that they can share it with all of the creatures they love. This is a message we can respond to positively at any age.


©2016 Chicago Botanic Garden and my.chicagobotanic.org

Leaves are green. There are very few exceptions in healthy living plants, and most of the exceptions are partially green with red, yellow, orange, or white patterns; or they look white, but upon closer inspection they are actually whitish, bluish-green, and not pure white. The pigments that give all leaves their color are essential for the plant’s ability to harness energy from the sun and make sugars in the process we know as photosynthesis.

But every once in a while, a completely white seedling sprouts from a seed. This happened with some basil I grew a few years ago. 

 

PHOTO: this picture shows two seedlings, one has two green seed leaves and the other is white and only half as big.

The green and albino seedlings came up at the same time, but the albino seedling never grew true leaves, and eventually withered and died.

My albino basil survived only a few days. Without any chlorophyll—the green pigment necessary for photosynthesis—this seedling was doomed. That is the case with all albino plants. The gene mutation that gives rise to albino plants is fatal to the plant, because without the ability to make sugars, the plant runs out of energy to live.

So when I was perusing the online Burpee seed catalog and came across “variegated cat grass” I was curious. VERY curious, and perhaps you are, too.

PHOTO: a potted plant of white grass leaves.

How can this albino plant survive? (Photo permission from W. Atlee Burpee Company)

I had several questions: 

  • The term “variegated” implies that the leaves would be striped or multicolored, but in the picture it appears that there are all white leaves. What will this grass actually look like?
  • How long will it take to sprout?
  • How easy it to grow?
  • Is there enough green on those leaves for the grass to survive or will it die off like my basil?
  • If it does survive, how long can I keep it growing?

And most importantly:

  • Would this make an awesome science activity for students in the classroom and at home to investigate the importance of chlorophyll in plants?

There was only one way to find the answers. I ordered the seeds and grew some variegated cat grass in our nature lab at the new Learning Center. You can do this in your classroom to find answers to my questions and your own. 

Before I give you directions for growing cat grass, you may be wondering:

What IS cat grass?

The cat grass you may have seen sold in pet stores is usually a type of wheat, or Triticum. Our “variegated cat grass” is a type of barley (Hordeum vulgare variegata). Both are cereal grains that have been cultivated as food for hundreds of years. Both are sold commercially as cat grass because some cats like to chew on the leaves. Not being a cat owner, I don’t know if cats actually like this stuff, but apparently it sells.

Variegated barley was the result of science experiments on genetic mutations in barley seeds in the 1920s. The hybrid barley seeds have been packaged and sold by different seed companies because…well, they’re attractive and intriguing—they caught my attention.

How to plant cat grass, barley, wheat, or any grass seeds

You need:

  • A container that will hold soil at a depth of at least 2 inches; drainage holes are best, but not necessary
  • Variegated cat grass seeds (sold as “cat grass, variegated” and available at Burpee and other seed suppliers)
  • Potting soil
  • Water
  • A warm, sunny location for your plants

 

PHOTO: Twelve plants have sprouted, one green, three green and white striped, and the rest all white.

In less than a week, a few more than half of the twenty variegated cat grass seeds planted in this 4-inch pot grew to 4 – 6 inches tall. The taller plants are ready for a trim.

Fill the container with moist potting soil. Spread seeds on the surface of the soil. Cover seeds with a thin layer of moist soil and tamp the soil down so that most of the seeds are covered. It’s all right if you can see some of the seeds through the thin layer of soil. Place in a warm, bright location. The seeds will sprout in a few days, but may take a week depending on the room temperature.

If students plant their own individual pots, have them place 20 – 30 seeds in each 3-inch container. The seeds I bought came 300 to a pack, so that means you need at least two (maybe three) packs to have enough for everyone in the class.

PHOTO: most of the grass is all white, but there are nine or ten all or partially green leaves.

Half of the 100 seeds planted in this 8-inch pot have sprouted, and more should be coming up soon.

You can also use the whole pack in a 8- to 10-inch container, or even spread more seeds in a foil baking pan filled with soil to grow a carpet of grass. The more densely you plant the seeds, the closer the plants will grow together and it will look and feel more like a healthy lawn. A sparser planting makes it easier to observe individual plants. It’s up to you how you want to do it, really.

Keep the grass in a warm, sunny location. Water when dry, but do not allow it to dry out. When the grass leaves are more than 3 inches tall, use a sharp pair of scissors to trim them to a uniform height just as you would mow a lawn. This will prevent the grass from going to seed and keep it alive longer. You can plant new seeds in the same planter to revitalize in two to three weeks when it starts looking a little tired.

Now the REAL science part: 

Whether you make a single classroom planter or have each student plant her own pot, observe your variegated cat grass for the next four to six weeks, or even longer. Keep it watered and trimmed. Measure its growth. Take photos or sketch it to record how it grows and changes. Ask your own questions and try to find answers, and ultimately reach a conclusion about what happens to white plants. If you and your class are really interested, plant some more cat grass and change the procedure to test your own ideas. It’s that easy to do plant science in your classroom.

Want more albino plant science? Read on.

More activities for inquiring minds

You can experiment with other genetically modified albino seeds available through science supply companies.

PHOTO: A packet of genetically modified corn seeds and instruction booklet

Seed kits enable you to investigate different genetic traits, including the albino mutation.

Carolina Biological Supply Company sells hybrid corn that will grow white leaves and stems. I have planted these seeds and they work pretty well, but require a bright window or light and a warm environment to sprout successfully. A classroom kit contains soil, planting trays, and 500 seeds for a classroom investigation, and costs about $100. You can order just the seeds in packs of 100 genetic corn seeds that are all albino (90 percent of the seedlings will grow to be albino) for $18.50, or a green/albino mix—which means about 75 percent of seedlings will be green and 25 percent white, for $10.50. The latter enables you to compare the mutation to the normal strain. 

PHOTO: Ten white corn seedlings are a few inches tall.

Five days after planting, albino corn seedlings are beautiful, but ill-fated.

Nasco sells seeds and kits to investigate albino plants. Their “Observing the Growth of Mutant Corn Seeds” kit serves up to 40 students and costs $62.50. Nasco also has albino tobacco seeds with 3:1 green to white ratio, 1,200 seeds for $12.05. Tobacco seeds are smaller, and therefore more difficult for little fingers to handle than corn or barley. I have never tried growing them, but that might be my next science project this fall.

PHOTO: eight inch glass planter with green grass and label that says: Cat Grass (Barley).

After a two months, my densely planted variegated cat grass is thriving at the nature lab, even though it no longer resembles the catalog photo.

The answer to my question? Yes! This is an awesome science activity for students because it’s easy and demonstrates something really important—in fact, something essential to our existence!

You don’t need to purchase the fancy kits to investigate why plants are green. You can get a lot of good science learning out of a pack of variegated cat grass. All you really need to do is look around you and notice the colors in nature. Do you see white leaves anywhere? If you do, then there is probably a science investigation waiting for you.


©2016 Chicago Botanic Garden and my.chicagobotanic.org

Color the leaves to understand the shades of fall

All it takes is a little Chemistry 101

Kathy J. —  October 5, 2016 — Leave a comment

During the summer, tree leaves produce all the pigments we see in fall, but they make so much chlorophyll that the green masks the underlying reds, oranges, and yellows.

In fall, days get shorter and cooler, and trees stop producing chlorophyll. As a result, the green color fades, revealing the vibrant colors we love. Eventually, these colors also fade, and the leaves turn brown, wither, and drop. Then the trees become dormant for winter.

Download a coloring activity.

Fall Color at the Garden

There are four pigments responsible for leaf colors:

  • Chlorophyll (pronounced KLOR-a-fill) – green
  • Xanthophyll (pronounced ZAN-tho-fill) – yellow
  • Carotene (pronounced CARE-a-teen) – gold, orange  
  • Anthocyanin (pronounced an-tho-SIGH-a-nin) – red, violet, can also be bluish

Leaves are brown when there are no more photo-sensitive pigments; only the tannins are left.


Color these leaves according to the pigments they produce:

honeylocust leaf
Honey locust

Leaves turn color early in the season; the lighter carotenes glow warmly against the blue sky and green grass.

 

sugar maple leaf
Sugar maple

The fading chlorophyll, combined with xanthophyll, carotene, and anthocyanin, produce the spectacular show we anticipate every year. Leaves change slowly and over time may be any combination of the four pigments, ending in a brilliant flame of anthocyanin.

 

japanese maple leaf
Japanese maple

The darker anthocyanin hues turn these feathery leaves the color of shadows—fitting for the spooky month of Halloween.

 

sweetgum leaf
Sweetgum

Like the maple, this tree puts on an awe-inspiring display of xanthophyll, carotene, and anthocyanin all together.

 

ginkgo leaf
Ginkgo

Light filtering through the xanthophyll and lighter carotene of these leaves creates an ethereal glow. The ginkgo drops all of its leaves in a day or two.

 

sumac leaf
Sumac

The anthocyanin in these leaves makes them the color and shape of flames, and appears as fire against the duller colors of the surrounding landscape.

 

buckeye leaf
Buckeye

Carotenes recede quickly around the edges of the leaves as they prepare to parachute to the ground.

 

tulip tree leaf illustration
Tulip tree

A pale hint of chlorophyll mixes with xanthophyll and a touch of carotene as this tree shuts down for winter.

 

pin oak leaf illustration
Pin oak

This stately tree holds its anthocyanin-rich leaves through the fall. The color eventually fades, but the tree holds its pigment-less leaves through the winter.


Download a coloring activity. 

Facts about fall leaf colors:

  • Trees use the sugars they produce through photosynthesis to make all of the pigments we see.
  • The best fall color display comes in years when there has been a warm, wet spring; a summer without drought or excessive heat; and a fall with warm, sunny days and cool nights.
  • Chlorophyll, carotene, xanthophyll, and anthocyanin are also responsible for the coloring of all fruits and vegetables, including corn, pumpkins, beans, peppers, tomatoes, and berries.
  • Peak fall color comes earlier in northern latitudes than southern latitudes, so if you miss the best of the sugar maples in Chicago, take a trip south to get your color fix.
  • You can preserve a leaf by ironing it between sheets of wax paper.

Fall color(ing) activity correct colors:

Fall Color(ing) Activity Answers


Illustrations by Maria Ciacco
©2016 Chicago Botanic Garden and my.chicagobotanic.org